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Earthly Matters
Health Center Stands on Rock-Solid Ground
February 21, 2000

The Health Center stands on firm ground. Ground tough enough to survive the down-cutting of rivers, the crushing power of ice sheets, and the violent shaking of rare, but powerful, eastern earthquakes. The prominent hill on which the Health Center stands will last forever. At least, in human terms.

The secret of its durability is lava. Crystallized lava. Massive, dense, black lava. Beneath the egg-shaped hill on which the Health Center sits is an ancient layer of volcanic rock called the Holyoke Basalt, a stratum more than 300 feet thick. On the outside it is tinged an orange-brown color by rust; on the inside it is speckled black and gray with crystals of pyroxene and plagioclase.

This sheet of basalt was once a red-hot silicate pudding that cooled and cracked in place, ever so slowly, 187 million years ago. Early dinosaurs would have seen plumes of sulfurous steam rising above the hardening lava. At that time, the Atlantic Ocean did not exist. Instead, eastern North America was welded to Africa, Europe and Greenland within a super-continent called Pangea.

The climate was dramatically monsoonal, alternating between bright, parching summers and warm drenching winters. Life was dominated by slithering reptiles, enormous ferns, resinous conifers, and trees known as cycads that resembled modern palms and pineapples. The soils were reddish brown.

Then everything changed. Thermal expansion within the earth lifted New England upward, forcing its brittle crust to spread both east and west above a warmer, softer layer. Central Connecticut, located on the crest of the rise, collapsed downward like the keystone of an arch, creating an elongated rift valley not unlike that of East Africa today, one complete with emerald-colored lakes, broad sandy deltas, smoldering volcanoes, and Jurassic creatures.

Later, after the lake had evaporated completely, one of the fractures in the rift tapped into a subterranean chamber of magma (molten rock). On three separate occasions, liquid basalt oozed upward, filling the shallow lake with lava instead of rainwater. After hardening, the lava was buried by layers of mud and sand, and it then tipped eastward as part of a giant crustal block.

Eventually, the package of tilted strata was dissected by streams that washed their load of sediment to the nascent Atlantic via the ancestral Connecticut River. During this epoch of erosion, the east-tipping sheet of basalt, being locally resistant, emerged as a high, west-facing ridge.

Millions of years later it was scoured by glacier ice and molded into a smooth, egg-shaped hill standing 450 feet above sea level, 150 feet above the valley below.

In addition to being sited on a sunny hilltop, the Health Center faces south-southwest, the warmest and brightest direction. The dark rocks on which it was built absorb solar energy during the day, releasing it invisibly at thermal wavelengths during the night. Stand still for a moment on that hilltop and you may feel the comforting radiant heat and strength of ancient times.

Robert Thorson